A. Field of the Invention
The present invention relates to a semiconductor device manufacturing method and a semiconductor device manufacturing device which can detect the position of a crystal defect with ease.
B. Description of the Related Art
Silicon carbide (SiC) is expected to be used as the next-generation semiconductor material. A semiconductor element made of SiC is characterized in that the resistance (on resistance) thereof in an on state can be reduced to a few hundredths of that of an element made of silicon (Si) and the semiconductor element can be used under a high-temperature environment of 200° C. or more.
SiC has a material advantage over other semiconductor materials. That is, SiC is characterized in that 4H-SiC has a band gap of 3.25 eV that is about three times more than the band gap, 1.12 eV, of Si and SiC has an electric field intensity of 2 mV/cm to 4 mV/cm that is about one digit greater than that of Si. SiC is experimentally used to manufacture various types of devices including rectifying devices, such as diodes, and switching devices, such as transistors and thyristors.
However, there are various crystal defects or dislocations in the SiC substrate. When an epitaxial film is formed on the SiC substrate, the number of crystal defects tends to increase. In a silicon carbide semiconductor device, such as a Schottky diode which is formed using the SiC substrate, the crystal defect causes a reduction in breakdown voltage or an increase in leakage current.
Therefore, it is necessary to acquire information about the position of the crystal defects in the plane of a wafer or the type of defects before a semiconductor device is manufactured using the SiC substrate. An inspection device satisfying the necessity has been proposed (for example, see JP 2007-318029A, JP 2007-318030A and JP 2007-318031A). JP 2007-318029A and JP 2007-318030A disclose a technique which inspects the distribution of crystal defects using an electroluminescence method. JP 2007-318031A discloses a technique which radiates excitation light to a measurement position or applies a voltage to emit light thereto and detects the emitted light at a plurality of measurement positions to map the position of the crystal defect.
However, in the above-mentioned methods, a very small deviation in the position of the detected defect occurs in each measurement operation, depending on the shape of the SiC substrate or the position of the SiC substrate relative to the inspection device. Therefore, when the semiconductor substrate is divided in a semiconductor device manufacturing process, it is difficult to easily determine the position of a semiconductor device including the crystal defect, even though an inspection device is used.
The invention has been made in view of the above-mentioned problems and provides a technique that can easily detect the position of a semiconductor device including the position of a crystal defect on a semiconductor substrate.